1. Technical Field
The present disclosure relates to biological information detection devices and, more particularly, to a biological information detection device, a biological information detection method, and a psychological change detection method for detecting biological information, such as heartbeat, in a non-contact manner.
2. Description of the Related Art
Heartbeat, blood flow, blood pressure, and blood oxygen saturation are widely used as basic parameters for determining the health condition of a person. These pieces of biological information relating to blood are typically measured by contact-type measuring instruments. Since contact-type measuring instruments are attached to the body of a subject, measurement, especially, long continuous measurement, sometimes incurs the subject's discomfort.
Various attempts have been made to easily measure basic biological information for determining the health condition of a person. For example, Japanese Unexamined Patent Application Publication No. 2005-218507 discloses a method for detecting heart rate in a non-contact manner on the basis of image information of a face or the like obtained with a camera. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2003-517342 discloses a method for measuring, using a white light source and a laser light source, blood oxygen saturation on the basis of a laser Doppler effect of laser light scattered behind the surface of a living body. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2014-527863 discloses a method for measuring, using an ordinary color camera, blood oxygen saturation while removing the influence of ambient light.
In addition, many methods for estimating a psychological change of a person have been proposed. For example, Japanese Unexamined Patent Application Publication Nos. 6-54836 and 2008-237244 disclose methods for detecting, with thermography, a decrease in temperature at a nose portion that occurs when a person feels stress (nervous) or concentrates.